Conventionally, a material testing machine is known in which right and left driving screws for elevating a crosshead are driven by a motor to elevate the crosshead to exert a test force on a specimen and the specimen is evaluated (for instance, see Patent Document 1). This kind of material testing machine is sometimes used to perform tests with a mounting fixture such as an illumination lamp or a protection shield being fitted to a main body of the material testing machine. For instance, the material testing machine disclosed in Patent Document 1 includes a crosshead that is moved up and down through right and left drive screws. The drive screws are concealed by support poles each having a surface in which there is formed a slot of a T-shape in cross-section that permits mounting fixtures to be fitted therethrough. The support poles are formed by extrusion of aluminum.    Patent Document 1: U.S. Pat. No. 36,392